1. Field of the Invention
This invention relates to a trailer with a tractor hitch and hydraulic pump, and in particular, to a tractor hitch assembly having a hydraulic pump attached thereon and further attaching to a tractor tongue extending through the trailer structure.
2. Background & Description of the Related Art
In farming operations, various agricultural implements are commonly pulled and powered by an agricultural tractor. The implements, such as a spreader, normally have a pivoting tongue which is affixed at one end to a tractor drawbar, and, at the other end to the implement. Mechanical power to the implement is often provided by a power-take-off (PTO) shaft of the tractor. The PTO may provide direct drive to the mechanical components of the implement or may power a hydraulic pump which, in turn, provides hydraulic power to the various components of the implement.
Mechanically driven pull-type agricultural implements couple to hitch arms of the tractor and have a mechanical linkage which connects the PTO shaft of the tractor to the mechanically driven elements of the agricultural implement thereby communicating power. Often, however, it is desirable to provide power to the drive elements of the agricultural implement hydraulically. Although hydraulic drive systems generally result in poorer drive transmission efficiencies compared to mechanical drive systems, hydraulic drive systems generally offer more accurate control of input torque, less maintenance of the system and fewer moving parts.
Hydraulically driven pull-type agricultural implements are generally provided with a pump having a drive shaft that attaches to the PTO shaft of the tractor. The hydraulic pump generates a flow of high pressure hydraulic fluid which passes through a hydraulic line to a motor or driven element of the agricultural implement. A return line runs from the driven element through a filter and into a sump tank which is commonly provided as the hollow interior of a tubular hitch arm or other reservoir capable of storing the hydraulic fluid.
Simple construction of a hydraulic drive system typically comprises a direct mechanical connection between the PTO shaft and the drive shaft of the hydraulic pump. It is common to mount the pumps to control hydraulic systems on tow behind implements on the implement itself, particularly where the hydraulically operated equipment on the implement requires high pressure and flow rates requiring a larger pump. In existing applications, with the pump mounted on the implement, a relatively long PTO shaft is connected between the tractor and the pump for driving the pump. The increased length of the PTO shaft reduces the turning radius of the tractor relative to the implement and increases the risk of damaging the PTO shaft when turning.
Pull-type agricultural implements are commonly supported by a frame which is supported by a plurality of wheels. As disclosed by the prior art, it is common for a trailer to have a box type frame with two longitudinal supports arranged at a transverse distance from one another and fixedly connected with a front and a rear transverse support. The horizontal orientation of the frame with the longitudinal supports and the transverse supports provide a frame having a width over its entire length corresponding to the length of the transverse support. A shortcoming of such a trailer frame is that the trailer requires significant bracing to support the heavy load of an agricultural implement such as a spreader and torqueing of the frame while turning. The increased weight associated with the additional bracing increases the fuel costs associated with agricultural operations.
In order to improve upon the shortcomings of the prior art, a trailer assembly is needed that reduces the weight of the trailer assembly and sufficiently supports a hydraulic pump without.